For at least the fifth time since early March, an air traffic controller fell asleep on the job today in Miami, prompting negotiations between the government and the controllers' union to change the way controllers are scheduled to work.

The incident during the midnight shift did not cause any harm, and the controller was working alongside others, but it did again raise major concerns over safety that many feel must be the final straw in the string of incidents since March.

The Federal Aviation Administration acknowledged that there is a widespread problem with fatigue among controllers and that the organization must institute changes in work schedules.

"We are taking important steps today that will make a real difference in fighting air traffic controller fatigue. But we know we will need to do more. This is just the beginning," FAA Administrator Randy Babbitt said in a statement.

The government has said that within 72 hours, new rules for controllers will be announced. Sources have told ABC News that this will include more time off between shifts, to allow for appropriate rest.

This morning's incident occurred at a busy Miami radar facility that handles high altitude air traffic for much of Florida, portions of the Atlantic Ocean and the Caribbean Sea. According to the FAA the controller, who has now been suspended, did not miss any calls from aircraft and there was no impact on flight operations.

In total there have now been at least seven incidents since the start of the year in which a controller is believed to have fallen asleep on the job on the midnight shift. One case occurred earlier this week in Reno when a controller missed a radio call from a plane carrying a seriously ill passenger.

Though other controllers attempted to help, the pilot ultimately had to land the plane by himself.

Air Traffic Controllers Sleeping on the Job: A Problem of Scheduling

Controllers often bounce from morning shifts, to afternoon, to night shifts, leaving little time for the body to adjust. Fatigue experts like Philip Gehrman, director of the Behavior Sleep Program at the University of Pennsylvania, said it is crucial that their shifts remain more constant.

"It would be nice if there were a greater appreciation that our bodies have a limit -- we're not equally able to function at all hours of a 24-hour day," Gehrman said.

FAA Administrator Randy Babbitt and Paul Rinaldi, president of the National Air Traffic Controllers Association, are scheduled to visit air traffic control facilities Monday to hear what controllers have to say and to remind them that sleeping on the job won't be tolerated, according to The Associated Press.

Rinaldi said exhaustion was most likely the culprit in the incident in Miami, where there were 12 controllers on duty along with two managers.

"It is never acceptable when we don't provide the level of service expected and required of us on every shift," he said. "We take our responsibilities very seriously and believe fatigue is a significant factor in these instances."

Though napping on duty is strictly forbidden, the AP reported that current and former controllers admitted that sleeping on the midnight shift is an open secret.

"It has always been a problem," said Rick Perl, who at one time was an instructor at FAA's academy for new controllers in Oklahoma City, Okla.

"There is no way you can get off at 2 p.m. in the afternoon and be back at 10 p.m. at night and get decent sleep."

According to a fatigue study by FAA and the National Air Traffic Controllers Association, scheduling of air traffic controllers often does not give them time to adjust to any one set of waking and sleeping hours.

Often they will work a week of midnight shifts, then a week of morning shifts, then a week of swing shifts beginning in the afternoon -- such changes can take an exhausting toll on the body and mind.

The chief in charge of the study recommends controllers be allowed sleeping breaks of as long as 2.5 hours during midnight shifts.

In a column posted Friday on USAToday.com, Babbitt and Rinaldi said the agency will review training and curriculum to "make sure our new controllers have mastered the right skills and learned the right disciplines before they start their careers."